Overhead handling method and system for high order data streams

A method for fast and economic handling of overhead bytes of an incoming high order data stream to form a corresponding outgoing high order data stream, the method comprising a) presenting the incoming high order data stream as a plurality of N component data streams transmitted in parallel, b) providing a common overhead processing unit (COHPU) capable of handling overhead bytes of a single one of the component data streams, c) forwarding overhead bytes of the component data streams to the COHPU in a circular order, while keeping docketing (ID) information for each particular overhead byte; d) processing each of the overhead bytes in the COHPU, and e) modifying the N component data streams to obtain an outgoing high order data stream based on results of the processing and the ID information with respect to each of the processed overhead bytes.